Import multiple non OBJ models?
You can do this by calling bpy.ops.import_scene.rip() as shown below:

import os
import bpy

path_to_rip_dir = os.path.join('C:\\', 'rips') #where C:\\rips\\ has the list of rip files

file_list = sorted(os.listdir(path_to_rip_dir))

rip_list = [item for item in file_list if item.endswith('.rip')]

for item in rip_list:
    path_to_file = os.path.join(path_to_rip_dir, item)
    bpy.ops.import_scene.rip(filepath = path_to_file)


You will need to install the addon first as mentioned in the readme file of the addon:


Blender 32 Bit:
   On 32 bit Blender installations, extract the downloaded ZIP file to
   C:\Program Files (x86)\Blender Foundation\Blender\2.77\scripts\addon
Blender 64 Bit:
      On 64 bit Blender installations, extract the downloaded ZIP file to
      C:\Program Files\Blender Foundation\Blender\2.77\scripts\addons
After you extract the Add-on, it will NOT show up in your
import/export list by default!
After extracting the Add-on, start Blender. Once Blender is
started, open up File->User Preferences, and navigate over to the
Add-ons tab. Find the add-on or search "NinjaRipper", and enable it. 
Click "Save User Preferences" on the bottom of the dialog, and close 
the dialog.
Now you will be able to use the Add-on.